DE1421785B2 - Method of supporting a glass sheet for treatment thereof at a glass deformation temperature - Google Patents

Description

The invention relates to a method of supporting a glass sheet for treating it at a glass deformation temperature at which the glass sheet is at least partially carried by applying gas under pressure against the undersurface of the glass sheet of a number of gas-supplying outlets, the gas being directed to gas-evacuation zones which are between the gas outlets, can flow.

In a known method of this type, an uninterrupted ribbon of glass is gradually im Cooling promoted to an annealing zone, the glass ribbon being carried through the gas layer. at Another known method of this type is the gas cushion carrying the glass ribbon through feed openings Generates gas flowing against the glass ribbon, the feed openings in channel-shaped Open the recesses of the tray.

The disadvantage of the known methods is that the promotion of individual at a distance from one another running glass panels do not allow with the necessary accuracy, since the contiguous Mass of an uninterrupted glass ribbon on a gas cushion thereby evenly carried and transported in the desired direction, however, individual glass sheets of different sizes cover the supply openings only partially in their entirety, so that pressure differences in the gas cushion arise that lead to different support of the glass panel in the individual surface areas to lead. This causes undesirable deformations and damage to the glass panel.

The invention is accordingly based on the object of providing a method of the type mentioned at the beginning to create ', with which it is possible to create individual spaced apart glass panels without deformation or to promote damage with even support.

This object is achieved according to the invention in that the lifting gas has a glass deformation temperature has to keep the glass at the deformation temperature, and that an essentially negligible Pressure drop between the gas discharge zones under the supported glass panel and a common gas discharge space or the atmosphere exists in comparison to the pressure drop between the gas source and the outlets supplying the gas.

With this method it is achieved that the at the respective feed openings, which the individual Glass panel approaches, the prevailing pressure increase is compensated, so that the respective in the direction of movement The leading edge is not exposed to a sudden increase in pressure and is corresponding Expose the edge at the back to a sudden drop in pressure. This will be for a Uniform transfer from one feed opening to the other is taken care of and uniform Support also brought about individual glass panels following one another at a distance.

It is advantageous if here the pressure drop between the gas source and a gas supplying one Outlet, which is covered by the glass sheet, is at least twice as great as the pressure drop between the covered outlet and the outflow area. Here, the pressure drop can go along the paths of gas flow to open-topped chambers, such as the gas-supplying outlets at reduced openings spaced from the upper ends of the chambers increase.

The even distribution of the outflowing gas is further favored if a substantial one Part of the gases that are introduced into the open ends of the chambers is directed so that a direct impact on the overlying glass panel is avoided. Doing this will be more beneficial Route the gases that are introduced into the chambers ίο, which are open at the top, initially against the lateral boundary walls and / or the bottoms of the chambers directed.

A device for carrying out the method according to the invention consists of a bed with a number of spaced apart, open-topped chambers, the upper ends of the chambers lie in a common generating area and gas flow zones next to the chambers open at the top are arranged. According to the invention, for this purpose, the pressure drop is brought about by Herao openings for the introduction of gases to these chambers and means for heating the gases, which are supplied to the open-topped chambers, the gas discharge zones so shaped are that they form a lower resistance to the gas flow than the openings. The openings for introducing the gases to the chambers can preferably be arranged in such a way that that they direct the gas flow away from the upper ends of the chambers.

The gas discharge zones are expediently directly with passage means of larger cross section tied together. The total cross-section of the open-topped chambers over a glass support section of the Bed can be larger than the total cross-section of the gas discharge zones of this section. In advantageous Thus, the total cross-section of the chambers open at the top is over a glass support section of the Bed approximately between S and 50% of the cross-section of this section.

The evenness of the respective gas attack

at the edges of the glass panels lying on the outside in the conveying direction is further favored if the above open chambers are arranged in rows which are inclined with respect to the movement path.

The invention is explained in more detail below with reference to exemplary embodiments in the drawing.

F i g. 1 shows a perspective view of a device for heating and transporting Glass panels to which the invention applies;

F i g. Figure 1A is a partial perspective view of the apparatus of Figure 1;

F i g. 2 shows in section two of the supply openings arranged next to one another;

Figure 3 is a diagram of the underneath the glass panel forming pressure conditions;

F i g. Fig. 4 shows in section an embodiment of a different configuration of the feed openings;

F i g. 5 shows a diagram of the pressure conditions in the arrangement according to FIG. 4;

F i g. Figure 6 shows, in plan view, an embodiment for the arrangement of chambers and outlet conduits;

Fig. 7 is section VII-VII of Fig. 6;
F i g. 8 is the section VIII-VIII according to FIG. 1;
F i g. 9 is a top plan view of the gas carrier bed

3 4

according to the F i g. 1 and 1A with the inclined rows, first, that the uncovered molded body from the arranged chambers. supported glass the gas from the common The device according to F i g. 1 has let a preheating storage space escape quickly, whereby the section 100, in which the glass is preheated , pressure in the storage space would be reduced and a heating section 200, in which the glass 5 thus necessarily also in the covered panels by a gas support bed to be worn, a form body; secondly, it prevents changes from cooling device 3 and a removal device of the load above a module by influencing the module with removal rollers with which the outflow of the gas flow from the storage space into chilled glass out of the device; thirdly, it reduces the amount of stress. io kung of all minor changes to the memory in the in F i g. 1A, the pressure is applied in relation to the pressure within the glass sheets 1 to be treated, initially by means of the module. In this embodiment, the gap is a schematically indicated H eizeinrichtun g 17 between the upper end of the module and the above a Ro llenfördere rs 20 preheated and the lower surface of the supported glass itself is then conveyed to a gas support bed, at its 15, namely on a uniform Size longitudinal side transport rollers 37 are arranged over the entire upper circumference of the module, which engages on an outer edge of the glass sheet 1 and is a function of the weight of the supported glass and this is further transported in the direction of arrow 2. This happens because the gas flow from the. In the course of the conveying direction, that of the storage chamber through the module and the Aus-A bkuhlein rLcfatung 3, which for example pass through two throttling points, serves the temperature of the glass panel and also has to open from above: The openings 151 in the base each of the glass sheet acting supply openings for cooling module and the gap between the upper end of the gas contains. This can be done above and below the module and the supported glass. Since the gap half-way cooling and storage chambers 83 and 84 is provided for a coolant, normally in relation to the openings IS1. 25, there is a practically constant pressure drop through the openings from the storage chamber in the area adjoining the conveyor rollers 20 The pressure per unit area 31, which are arranged in rows, which, measured obliquely in the cross section across the module, run to the movement path of the glass panels 1. This is equal to chambers 31 under normal equilibrium conditions Connected via a piece of pipe 32 to a 30 of the weight per unit area of the supported glass storage chamber 33, which in turn has an area that it supports, the gap between the gas burner being heated through openings 35. Module and the glass in terms of its size between the individual chambers are outlet pipes adjusted until this pressure is reached (ie, it 39 angeo That is, which is connected to an outlet space or which is the height of the support of the glass from the ambient air. 35 module changed). So if the gap is formed as a result of a correspondingly high weight of a piece of glass or as a result of a force acting on the glass from the outside in the tempering section 3 on the underside of the glass sheet, with the difference that the chambers are small, then take the pressure within the module 81 has a lower level and the supply pipe closes until the pressure with the load in the same piece 82 is smaller in cross-section but is longer in weight or until the pressure of the storage chamber is formed than the pipe pieces 32 previously is reached as soon as the gap width exceeds the value going section. Reached zero. If the gap width decreases to zero, F i g. 2 shows the chambers 31 in the section in the section following the conveyor, then of course an insufficient pressure roller 20. As if exerted on the load so that no support from F i g. 2, the gas is released from a 45 tongue. The glass lifts off the module gas source in the direction of the arrows 10 lines 164 as a result of the gas pressure in the module, which is fed to the inside of the pipe socket 32, acting on the lower surface of the glass, and reaches the upper end of the lines 164 Nozzle head a value below each module pressure, which is greater than 150 on the basis of a vertical line 163, than the weight of the glass, to which the nozzles in the form of horizontal 50 connect the dimensions of the gap and reduced channels 151 , 'the pressure of the module on the outer surface. In this way, the head 150 is adjusted. In this way, the gap is set to a uniform dimension, the outflowing gas in the direction of the arrows 11 is little dependent on the weight of the glass, the pressure at least partially against the side walls and / or in the storage space and the size of the mouth. Bottom of the chamber 31 directed and there umgele nkt, 55 gen. The extent to which the pressure inside to escape in the direction of the arrows 12 upwards. of the module increases with a decrease in the gap, is here the outflowing gas against the in Rieh- a function of the size of the gas flow in the direction of the arrow 2 moving glass panel 1 in module and the gas volume in the module, tet and on This over the side edges of the chambers The mouth must therefore deflected for a given pressure 31 in the direction of the arrows in order not to be so small in outlet 60 in the storage space that it can reach the lines or gas outlet zones 77 a, gas flow in each module so far restricts that to which an expanded space 77 and then an extraordinarily long time is required to connect to the pipeline 39. Best causes the pressure to increase as a function of a decrease in the relatively small support space. In most of the size of the mouth 151 of the nozzle 150 a sufficient amount of gas should come within the case of the gas pressure from the interior of the storage chamber of a time of not more than one second, generally to the interior of the module and met on this base Even less than 0.1 second in the Kam mode has three important functions: It prevents any further entry and preferably suddenly stops

5 6

to deliver the higher pressure required to vertical conduit 170 and horizontally thereon

in order to prevent the glass from reaching the uppermost module-adjoining channels 172 which form the nozzles

edge touched. are provided. As can be seen from Fig. 7, the

Small volume modules are suitable for the outlet conduits 167 in the shape of a channel between the

This purpose is better arranged than larger modules with a front 5 individual walls, whereby on the channel floor

given size of the flow. In general, connect outlet pipes 168 in each case,

the modules in the subject matter of the invention have a Fig. 8 is the section VIII-VIH according to Fig. 1 and

Volume below 410cm ³ , preferably not leaving the construction of the heating device 17 with heating

163.9 cm ⁸ and particularly desirable are volumes of spools 18 between brackets 19 and the

below 32.78 cm ³ . By the fact that the io construction of the gas support bed 30 and the drive of the trans-

Recognize support rollers from identically constructed modules 37 via a gear 40 to 47,

builds and leaves it with a uniform pressure. Furthermore, F i g. 8 the arrangement from below the

ensures, each module supports the heating coils 18 arranged above it in holding

Tcile of the glass film or the glass plate along a stanchions 19 of an additional heating device 16

Desired area. Because neighboring 15 know. Ventilation devices are loaded with 38

Modulc are relatively close together, it is shown. Via the line 34 is carried out by means of gas

cine practically uniform support under the burner the loading of the storage chambers

whole area of glass film and a product that 33 (Fig. IA).

is practically free from damage. F i g. 9 shows the inclination of the

Those of the F i g. FIG. 2 assigned to FIG. 3 shows in the slide 20 individual rows of chambers 31 can be seen, with

gram the pressure distribution formed in this way over one of these rows in relation to the trajectory of the

Cross-section of the gas bed and reveals that the glass panels are inclined. The mode of action of the

that in this way relatively large areas 14 written arrangement is the following:

Even pressure can be achieved, the upper glass film with a nominal thickness of 6.35 mm

half of atmospheric pressure PO and only 25 and about 40 cm wide and 1.50 m long are in

because it has practically no effect on the glass panel - the longitudinal direction in sequence on the roller

end small areas 15 are interrupted, conveyor 20 is placed and then through the preheating

in which the pressure drops very sharply. As can be seen - section 100 at a linear velocity of

borrowed, the areas of pressure drop due to the 2.6 cm per second are passed through. In this way

Overflow over the edges of the chambers 31 in 30 are an average of 90 pieces of glass per hour

Cross-section smaller than the cross-section of the gas conveyed through the whole system. The electric

outflow zone 77fl. Heating coils 18 above and below the moving

F i g. Figure 4 shows another embodiment for the wegenden glass to support the heating effect

Structure of the chambers and the nozzles, with those in the preheating section with an average

Fig. 4 illustrated embodiment of the chamber 35 input power of approximately 32JcW _v to the

training in the area of the tempering section 3 ent- bring the temperature of the glass to about 510 ° C,

speaks. The pipe socket used for gas supply, which is measured on the surface and at a

82, which reach through the cooling chamber 83 and the conveying speed for the glass of approximately

end in a storage chamber 84 , the head is 4.57 m.

separately attached chambers 81, into which nozzles 40 As soon as the leading edge of the glass film is the last

heads 159 protrude, which leaves the preheating section with a horizontal subsequent roller and

At the end and the ducts 87 forming the nozzles change the chambers 31 which form the support bed 30.

are beautiful. The distance between the nozzle heads 159 and the, leaves, the film is only partially and finally

adjacent walls of the chamber 81 is little borrowed entirely from the uniform pressure of the gas

Ger than in the embodiment according to FIG. 3, so 45 carried, which flows out of the chambers. Because now

that due to the different cross-sectional shape, the pressure- the chambers have little or no supporting effect-

vcrtcilation over the entire cross-section of the exercise, if they are only partially covered with glass,

drive opening closer to the in the direction of the rows are at a certain angle from the

Arrow 2 moving glass sheet 1 is formed. Perpendicular to the transport path of the glass

Wic shown is directed in section 3 above the 50, so that the edges of the glass film to the min-

Glass panel 1 a correspondingly designed chamber mines are always worn at certain intervals,

arrangement provided. In addition, this alignment guarantees a

F i g. 5 again shows the pressure distribution over uniform heating of the glass by the fact that half of the gas support bed with sections 88 is prevented that parts of the glass in the longitudinal pressure, which extend over large areas 55 in the direction of the heating zone only over the outflow and only through very small areas Sections areas migrate, as would be the case if the 89 are interrupted with greater pressure drop. Chambers in the direction of movement of the glass

F i g. 6 shows a plan view of another embodiment. Once the glass is through

shape for the formation of the chambers of the gas, then it is

Gastragbettcs, the chambers 166 common 60 tion and by frictional engagement of its lower

or wall parts 169 adjoining one another have an edge with the surrounding transport parts 37

and the outlet conduits 168 transported alongside the rest. To that end is the whole system

Wall parts of these chambers lie. The nozzle heads in a common plane at an angle of

are in Fig. 6 denoted by 171. Inclined 5 ° to the horizontal to give the glass a

F i g. Figure 7 is plan view VII-VII of Figure 7. 6 and 65 component of force to give T ^ which is perpendicular to the

lets the arrangement of a common storage cam traction sheaves be directed.

mcr or storage line 174 for the gas supply to gas burners are supplied with natural gas and air

recognize the nozzle heads 171 , which in turn are fed with a volume percentage ratio of approximately 36,

with an excess of 260% air volume over the air volume required for complete combustion. The natural gas is supplied at approximately 169.92 dm ³ per hour with a cross-sectional area of 929 cm ² . The combustion products are added to the storage chambers and generate a pressure in them of approximately 0.35 kg / cm ^2. Each chamber 31 has openings which reduce this pressure in the chambers when they are covered by the glass to about one twenty-first of the storage pressure The gas is fed to the stem of each chamber at a temperature of 650 ° C. and a flow rate of approximately 36.816 dm ³ per minute.

The chambered bed in this embodiment consists of 120 chambers per square foot (929 cm ² ). The top of each chamber is square, the outer sides are 25.4 mm long, and the spacing between the boundary walls of adjacent chambers is 2.38 mm. Each wall is 1.587 mm thick. For each square foot (929 cm ² ) of glass area, this bed construction offers a gaseous support area of 590 cm ² (that is the inner area of the chamber at its upper edge), 154.0 cm ^{2 of} gas outlet area and 182 cm ^{2 of} wall area of the chamber that contains the supply areas from the outflow areas'. The nominal chamber support pressure when covered by glass 6.35 mm thick is 0.0161 kg / cm ² more than the pressure above the glass surface, which has a nominal distance of 0.0254 mm between the underside of the glass supported by the gas film and maintains the top of the chamber wall. The nominal discharge pressure is practically one atmosphere absolute.

The heat is supplied to the glass plates by means of convection and heat radiation from the support gas, which is at a temperature of approximately 650 ° C, and the chamber by means of radiation from ceiling heating coils 18 with a temperature of at least 10 ° C above that of the Glass is additionally supplied, i.e. generally at over 700 ° C. If no glass is supplied to the furnace at all, then an average power of approximately 30 kW is maintained. As soon as the supply of glass into the furnace begins, the heating elements are activated in order to be able to supply the heat according to the fluctuating heat requirements. The temperature of the glass increases to approximately 650 ° C during the. Time during which the glass travels its distance of 4.57 m, corresponding to the length of the heating zone. The floor heating coils 18 below the storage chambers consume electrical energy in the average amount of 58 kW under the no-load conditions and provide the heat at a temperature of about 700 ° C in order to maintain the heat level and to keep the storage containers hot. Because heat must be applied to both the top and bottom of the glass sheets in order to prevent bending or other curvatures of the glass, the gas is introduced at approximately the same temperature as that at which the glass is finally heated. The level of radiant heat energy (i.e. the temperature level) above the glass is then adjusted to compensate for the heat emitted by

60 reaches the bottom of the glass with the aim of keeping the glass film smooth and level. For example, glass which is convexly curved upwards often shows an excess of radiant heat in the first heating zones or also in the quenching zone. The speed at which the glass is passed through the heating zone is then controlled in such a way that the exact heat input per unit glass surface and thus the exact temperature for the tempering in the subsequent quenching zone is obtained.

Claims (11)

Patent claims: A method of supporting a glass shelf for treating it at a glass deformation temperature at which the glass panel is at least partially supported by directing gas under pressure against the undersurface of the glass panel from a number of gas-supplying outlets , the gas to gas Abfüh rzone, which are between the gas outlets, can flow, characterized in that the carrier gas has a glass deformation temperature in order to keep the glass at the deformation temperature, and that a substantially negligible pressure drop between the gas discharge zones under the supported glass sheet and a common gas discharge space or the atmosphere compared to the pressure drop between the gas source and the gas supplying outlets. 2. The method according to claim 1, characterized in that the pressure drop between the Gas source and a gas-supplying outlet which is covered by the glass sheet, at least is twice as great as the pressure drop between the covered outlet and the outflow area. 3. The method according to claim 1 or 2, characterized in that the pressure drop along the paths of the gas flow to open-top .Kam numbers, such as the gas-delivering outlets, at reduced openings which are arranged at a distance from the upper ends of the chambers increases. 4. The method according to claim 3, characterized in that a substantial part of the gases, which are inserted into the open ends of the chambers, is directed so that a direct impingement on the overlying glass panel is avoided. 5. The method according to claim 3 or 4, characterized in that the gases in the above open chambers are introduced, initially against the side boundary walls and / or the bottoms of the chambers are straightened. 6. Device for performing the method according to one of the preceding claims with a bed with a number of spaced apart open top chambers, wherein the upper ends of the chambers lie in a common generator area and gas discharge zones are arranged next to the chambers open at the top, characterized by openings (151) for the introduction of gases to these Chambers and by means (34) for heating the gases leading to the chambers open at the top (31), whereby the gas discharge 009 532/162 zones (77 α) are shaped so that they have a lower resistance to the gas flow than form the openings (151). 7. Apparatus according to claim 6, characterized in that the openings (150) for introducing the gases to the chambers (31) are arranged so that they wegrichte the gas flow from the upper ends of the chambers (31) n. 8. Apparatus according to claim 7, characterized in that the gas discharge zones (77 α) ίο are directly connected to passage means (77) of larger cross-section. 9. Device according to one of claims 6 to 8, characterized in that the total cross-section of the open-topped chambers (31) over a glass support section of the bed greater than that Total cross-section of the gas discharge zones (77 a) of this section. 10. The device according to claim 9, characterized in that the total cross section of the chambers (31) open at the top over a glass support section of the bed approximately between 5 to 50% of the cross-section of this section is. 11. Device according to one of claims 6 to 10, characterized in that the open-topped chambers (31) are arranged in rows which are oblique g with respect to the movement path. For this purpose 2 sheets of drawings